Chlorinated vinyl-chloride-based resin

ABSTRACT

The present invention provides a chlorinated polyvinyl chloride resin that enables excellent continuous productivity in molding and that enables a molded article to have both processability and unevenness-preventing properties. Provided is a chlorinated polyvinyl chloride resin having, in Raman measurement by Raman spectroscopy, an average of a ratio (A/B) of a peak intensity A observed in a range of 660 to 700 cm −1  to a peak intensity B observed in a range of 600 to 650 cm −1  of 0.50 to 2.00, and a standard deviation of the A/B of 0.090 or less.

TECHNICAL FIELD

The present invention relates to a chlorinated polyvinyl chloride resinthat enables excellent continuous productivity in molding and thatenables a molded article to have both processability andunevenness-preventing properties.

BACKGROUND ART

Polyvinyl chlorides generally have excellent mechanical strength,weather resistance, and chemical resistance, and thus have beenprocessed into various molded articles and used in various fields.

Polyvinyl chlorides, however, have poor heat resistance. This has led tothe development of chlorinated polyvinyl chloride resins (CPVCs), whichare polyvinyl chlorides chlorinated to have improved heat resistance.

For example, Patent Literature 1 discloses a chlorinated polyvinylchloride resin obtained by a specific production method. PatentLiterature 1 discloses that such a resin has less initial discolorationin thermal molding and has excellent thermal stability.

CITATION LIST Patent Literature

Patent Literature 1: WO 2014/178362

SUMMARY OF INVENTION Technical Problem

However, the chlorinated polyvinyl chloride resin disclosed in PatentLiterature 1 contains many highly chlorinated portions, and thus iseasily decomposed by heat in molding and generates a large amount ofhydrogen chloride gas, contaminating the die surface. In addition,molded articles obtained in such a manner may have scorch marks, andthus may cause poor continuous productivity in molding and poor moldingprocessability. Moreover, the chlorinated polyvinyl chloride resin maynot provide a uniform molded article because the highly chlorinatedportions are difficult to uniformly mix with less chlorinated portionsdue to their difference in melt viscosity, thus causing great shapeunevenness in the resulting molded article.

In view of the technical problems in the prior art, the presentinvention aims to provide a chlorinated polyvinyl chloride resin thatenables excellent continuous productivity in molding and that enables amolded article to have both processability and unevenness-preventingproperties.

Solution to Problem

The present invention relates to a chlorinated polyvinyl chloride resinhaving, in Raman measurement by Raman spectroscopy, an average of aratio (A/B) of a peak intensity A observed in a range of 660 to 700 cm⁻¹to a peak intensity B observed in a range of 600 to 650 cm⁻¹ of 0.50 to2.00, and a standard deviation of the A/B of 0.090 or less. The presentinvention is described in detail below.

The chlorinated polyvinyl chloride resin of the present invention has,in Raman measurement by Raman spectroscopy, an average of a ratio (A/B)of a peak intensity A observed in a range of 660 to 700 cm⁻¹ to a peakintensity B observed in a range of 600 to 650 cm⁻¹ of 0.50 to 2.00.

The chlorinated polyvinyl chloride resin having an average of the A/Bwithin the above range can improve the unevenness-preventing propertiesof a molded article and provide excellent continuous productivity inmolding.

The average of the ratio (A/B) is preferably 0.80 or more and preferablyless than 1.30.

The average of the ratio (A/B) of the peak intensity A to the peakintensity B can be measured by the following method.

Specifically, first, Raman spectra of 50 particles of the chlorinatedpolyvinyl chloride resin in a powdery form are measured using amicro-Raman spectrometer. Each of the obtained Raman spectra is thenbaseline-corrected by linear approximation, and the peak intensity Bobserved in the range of 600 to 650 cm⁻¹ and the peak intensity Aobserved in the range of 660 to 700 cm ¹ are measured. The A/B iscalculated, and the average concerning the peak intensities iscalculated to determine the average.

In the chlorinated polyvinyl chloride resin of the present invention,the standard deviation of the ratio (A/B) of the peak intensity Aobserved in the range of 660 to 700 cm⁻¹ to the peak intensity Bobserved in the range of 600 to 650 cm⁻¹ is 0.090 or less.

The chlorinated polyvinyl chloride resin having a standard deviation ofthe A/B of 0.090 or less can further improve the unevenness-preventingproperties of a molded article and the continuous productivity inmolding.

The standard deviation of the A/B is more preferably 0.080 or less. Thelower limit of the standard deviation of the A/B is not limited, but ispreferably 0.010 or more.

The standard deviation of the A/B can be calculated based on the averageof the A/B and the A/B of each particle in the above Raman measurement.

The Raman spectrum analysis of the chlorinated polyvinyl chloride resinalso provided the following findings.

Specifically, the intensity of a peak derived from the CH stretching ofCH₂, observed at 2,921 cm⁻¹, and the intensity of a peak observed at2,977 cm⁻¹ varied depending on the method for producing the chlorinatedpolyvinyl chloride resin. Detailed analysis of these peaks will allowmore detailed analysis of structural differences in chlorinatedpolyvinyl chloride resins.

The analysis also revealed that a photo-chlorinated polyvinyl chlorideresin has a peak at 1,600 to 1,700 cm⁻¹ that is presumably derived froma double bond, and that a chlorinated polyvinyl chloride resindeteriorated by heating or the like has newly formed peaks at 1,131 cm⁻¹and 1,510 cm⁻¹ that are presumably derived from conjugated double bonds.

In the chlorinated polyvinyl chloride resin of the present invention,the average of the A/B and the standard deviation of the A/B preferablysatisfy the following relation.

0.500 [Average of A/B]+[Standard deviation of A/B]^(1/2)≤2.300

Preferably, the chlorinated polyvinyl chloride resin of the presentinvention contains structural units (a) to (c) represented by thefollowing formulas (a) to (c), and the proportion of the structural unit(a) is 5.0 mol % or higher, the proportion of the structural unit (b) is40.0 mol % or lower, and the proportion of the structural unit (c) is55.0 mol % or lower, relative to the total number of moles of thestructural units (a), (b), and (c). Such a chlorinated polyvinylchloride resin shows uniform gelling characteristics in melt kneadingand can provide a molded article with less unevenness on the surface.

In the chlorinated polyvinyl chloride resin of the present invention,the proportion of the structural unit (a) is preferably 5.0 mol % orhigher, more preferably 30.0 mol % or higher, still more preferably 35.0mol % or higher, and preferably 90.0 mol % or lower, more preferably60.0 mol % or lower, relative to the total number of moles of structuralunits (a), (b), and (c).

The proportion of the structural unit (b) is preferably 5.0 mol % orhigher, more preferably 15.0 mol % or higher, and preferably 40.0 mol %or lower, more preferably 30.0 mol % or lower, still more preferably25.0 mol % or lower, relative to the total number of moles of structuralunits (a), (b), and (c).

The proportion of the structural unit (c) is preferably 5.0 mol % orhigher, more preferably 25.0 mol % or higher, and preferably 55.0 mol %or lower, more preferably 40.0 mol % or lower, relative to the totalnumber of moles of structural units (a), (b), and (c).

[Chem. 1]

—CH₂—CHC1—  (a)

—CH₂—CC1₂—  (b)

—CHC1—CHC1—  (c)

The molar ratios of the structural units (a), (b), and (c) in thechlorinated polyvinyl chloride resin reflect the site to which chlorineis introduced at the time of chlorination of the polyvinyl chloride(PVC). The PVC prior to chlorination is in a state where the proportionof the structural unit (a) is 100 mol %, and the proportions of thestructural units (b) and (C) are 0 mol %. As chlorination proceeds, theproportion of the structural unit (a) decreases, while the proportionsof the structural units (b) and (c) increase. At this time,nonuniformity of the chlorinated state will increase in a case where theproportion of the structural unit (b), which is unstable, excessivelyincreases, or in a case where the chlorinated site and the unchlorinatedsite are unevenly present within the same particle of the chlorinatedpolyvinyl chloride resin. An increase in this nonuniformity causesvariations in gelling characteristics in melt kneading of thechlorinated polyvinyl chloride resin, which will severely impair thesmoothness of the molded article surface.

In contrast, in the present invention, setting the molar ratios of thestructural units (a), (b), and (c) within the above range enables thechlorinated polyvinyl chloride resin to have high uniformity and exhibitgood gelling characteristics in melt kneading.

The molar ratios of the structural units (a), (b), and (c) in thechlorinated polyvinyl chloride resin of the present invention can bemeasured by molecular structure analysis using NMR. NMR analysis can beperformed in accordance with the method described in R. A. Komoroski, R.G. Parker, J. P. Shocker, Macromolecules, 1985, 18, 1257-1265.

The chlorinated polyvinyl chloride resin of the present invention maycontain a different structural unit other than the structural units (a),(b), and (c) as long as the effects of the present invention are notimpaired.

The amount of the different structural unit is preferably 0% by mass ormore, and preferably less than 10% by mass.

In the chlorinated polyvinyl chloride resin of the present invention,the proportion of the structural unit (c) and the average of the A/Bpreferably satisfy the following relation.

0.5≤Proportion (mol %) of structural unit (c)/[Average of A/B]≤110

The proportion of the structural unit (c) and the average of the A/Bmore preferably satisfy the following relation.

3.8≤Proportion (mol %) of structural unit (c)/[Average of A/B]≤68.8

When the above relation is satisfied, the unevenness-preventingproperties of a molded article can be improved, and excellent continuousproductivity in molding can be achieved.

In the chlorinated polyvinyl chloride resin of the present invention,the amount of added chlorine is preferably 3.2 to 15.2% by mass.

When the amount of added chlorine is 3.2% by mass or more, the moldedarticle has sufficient heat resistance. When the amount of addedchlorine is 15.2% by mass or less, moldability is improved.

The amount of added chlorine is more preferably 5.2% by mass or more,still more preferably 8.2% by mass or more, and is more preferably 12.2%by mass or less, still more preferably 11.2% by mass or less.

A polyvinyl chloride typically has a chlorine content of 56.8% by mass.The amount of added chlorine means the proportion of chlorine introducedto a polyvinyl chloride, and can be measured by the method specified inJIS K 7229.

In the chlorinated polyvinyl chloride resin of the present invention,for a more uniform chlorinated state and for prevention of scorch marksin molding, the ratio of the proportion of the structural unit (b) tothe amount of added chlorine (Proportion of structural unit (b)/Amountof added chlorine) is preferably 0.1 or higher and preferably 4.0 orlower.

The average degree of polymerization of the chlorinated polyvinylchloride resin of the present invention is not limited, and ispreferably 400 or higher, more preferably 500 or higher, and preferably2,000 or lower, more preferably 1,500 or lower.

When the average degree of polymerization is within the above range,fluidity in injection and the strength of the molded article can be bothachieved.

The chlorinated polyvinyl chloride resin of the present invention is aresin obtained by the chlorination of a polyvinyl chloride.

The polyvinyl chloride used may be a vinyl chloride homopolymer, or maybe a copolymer of a vinyl chloride monomer and a monomer withunsaturated bond(s) that is copolymerizable with the vinyl chloridemonomer, a graft copolymer obtained by graft-copolymerizing a vinylchloride monomer to a polymer, or the like. These polymers may be usedsingly or in combinations of two or more.

When the polyvinyl chloride is a copolymer of a vinyl chloride monomerand a monomer with unsaturated bond(s) that is copolymerizable with thevinyl chloride monomer, or a graft copolymer obtained bygraft-copolymerizing a vinyl chloride monomer to a polymer, the amountof a component derived from the vinyl chloride monomer in the polyvinylchloride is preferably 90% by mass or more and preferably 100% by massor less.

Examples of the monomer with unsaturated bond(s) that is copolymerizablewith the vinyl chloride monomer include a-olefins, vinyl esters, vinylethers, (meth)acrylates, aromatic vinyls, vinyl halides, andN-substituted maleimides. These monomers may be used singly or incombinations of two or more.

Examples of the α-olefins include ethylene, propylene, and butylene.Examples of the vinyl esters include vinyl acetate and vinyl propionate.Examples of the vinyl ethers include butyl vinyl ether and cetyl vinylether.

Examples of the (meth)acrylates include methyl (meth)acrylate, ethyl(meth)acrylate, butyl acrylate, and phenyl methacrylate. Examples of thearomatic vinyls include styrene and α-methyl styrene.

Examples of the vinyl halides include vinylidene chloride and vinylidenefluoride. Examples of the N-substituted maleimides include N-phenylmaleimide and N-cyclohexyl maleimide.

Preferred among these are ethylene and vinyl acetate.

The polymer to which vinyl chloride is graft copolymerized is notlimited as long as vinyl chloride can be graft copolymerized. Examplesof such a polymer include ethylene-vinyl acetate copolymers,ethylene-vinyl acetate-carbon monoxide copolymers, ethylene-ethylacrylate copolymers, ethylene-butyl acrylate-carbon monoxide copolymers,ethylene-methyl methacrylate copolymers, and ethylene-propylenecopolymers. Examples also include acrylonitrile-butadiene copolymers,polyurethane, chlorinated polyethylene, and chlorinated polypropylene.These may be used singly or in combination of two or more.

The method of polymerizing the polyvinyl chloride is not limited, and aconventionally known method such as aqueous suspension polymerization,block polymerization, solution polymerization, or emulsionpolymerization can be used.

The chlorinated polyvinyl chloride resin of the present invention may beproduced by, for example, a method including preparing a suspension in areaction vessel by suspending a polyvinyl chloride in an aqueous medium,introducing chlorine into the reaction vessel, and heating thesuspension to chlorinate the polyvinyl chloride.

The average of the A/B and the standard deviation of the A/B can beadjusted by changing conditions for the polyvinyl chloride chlorinationsuch as pressure, temperature, chlorine concentration, chlorine dioxideconcentration, hydrogen peroxide concentration, chlorine consumptionrate, stirring conditions, light energy irradiation intensity, and lightwavelength.

The reaction vessel used may be a commonly used vessel such as aglass-lined stainless steel reaction vessel or titanium reaction vessel,for example.

The method of preparing the suspension of the polyvinyl chloride in anaqueous medium is not limited. For example, a cake-like PVC obtained bysubjecting a polymerized PVC to monomer removal treatment may be used,or a dried PVC may be resuspended in an aqueous medium, or a suspensionobtained by removing any substance undesired for the chlorinationreaction from the polymerization system may be used. It is preferred touse a cake-like resin obtained by subjecting a polymerized PVC tomonomer removal treatment.

The aqueous medium used may be ion-exchange-treated pure water, forexample. While the amount of the aqueous medium is not limited,generally, it is preferably 150 to 400 parts by mass based on 100 partsby mass of the PVC.

Chlorine to be introduced into the reaction vessel may be either liquidchlorine or gaseous chlorine. The use of liquid chlorine is efficient inthat a large amount of chlorine can be charged into the reaction vesselin a short period of time. Chlorine may be added in the course ofreaction to adjust the pressure or supply chlorine. At this time,gaseous chlorine in addition to liquid chlorine may be blown into thereaction vessel, as required.

While the gauge pressure in the reaction vessel is not limited, it ispreferably from 0 to 2 MPa, because the higher the chlorine pressure is,the more readily the chlorine will penetrate into the PVC particles.

The method of chlorinating the PVC in the suspended state is notlimited. Examples of chlorination method include a method in which theexcitation of bonding of the PVC and chlorine is brought about bythermal energy to accelerate the chlorination (hereinafter referred toas thermal chlorination); and a method in which light energy such asultraviolet light is applied to accelerate the chlorination byphotoreaction (hereinafter referred to as photo-chlorination). Theheating method in the chlorination by thermal energy is not limited, andfor example, heating with an external jacket from the reactor wall iseffective. The use of light energy such as ultraviolet light requires anapparatus capable of light energy irradiation such as ultravioletirradiation under high temperature and high pressure conditions. In thephoto-chlorination, the chlorination reaction temperature is preferably40° C. to 80° C. In the photo-chlorination, the ratio of the lightenergy irradiation intensity (W) to the total amount (kg) of the rawmaterial PVC and water is preferably 0.001 to 6 (W/kg). The irradiationlight preferably has a wavelength of 280 to 420 nm.

Preferred among the above chlorination methods is a thermal chlorinationmethod involving no ultraviolet irradiation. Preferred is a method inwhich the excitation of bonding of the polyvinyl chloride and chlorineis brought about by heat alone or by heat and hydrogen peroxide toaccelerate the chlorination reaction.

In the case of the chlorination reaction by light energy, the amount oflight energy needed to chlorinate the PVC is greatly affected by thedistance between the PVC and the light source. Thus, the amount ofreceived energy is different inside and on the surface of the PVCparticles, so that chlorination does not occur uniformly. As a result, aCPVC with reduced uniformity is obtained. In contrast, with the methodof chlorination by heat without ultraviolet irradiation, a more uniformchlorination reaction occurs to produce a CPVC with increaseduniformity.

The chlorination by heat alone is preferably performed at a temperatureof 40° C. to 120° C. When the temperature is excessively low, the rateof chlorination will decrease. When the temperature is excessively high,dehydrochlorination reaction will occur along with the chlorinationreaction, which causes discoloration of the resulting CPVC. The heatingtemperature is more preferably 50° C. to 110° C. The heating method isnot limited, and heating may be performed with an external jacket fromthe reaction vessel wall, for example.

In the chlorination, hydrogen peroxide is preferably further added tothe suspension. The addition of hydrogen peroxide can improve the rateof chlorination. Hydrogen peroxide is preferably added in an amount of 5to 500 ppm to the PVC per hour of the reaction time. When the amount ofhydrogen peroxide added is excessively small, the effect of improvingthe rate of chlorination cannot be obtained. When the amount of hydrogenperoxide added is excessively large, the thermal stability of the CPVCwill decrease.

When hydrogen peroxide is added as described above, the rate ofchlorination is improved, so that the heating temperature can be setrelatively low. The heating temperature may be 65° C. to 110° C., forexample.

During the chlorination, it is preferred to perform chlorination at achlorine consumption rate of 0.010 to 0.015 kg/PVC-kg·5 min after theamount of added chlorine reaches a value that is five percentage pointsby mass lower than the final amount of added chlorine, and furtherperform chlorination at a chlorine consumption rate of 0.005 to 0.010kg/PVC-kg·5 min after the amount of added chlorine reaches a value thatis three percentage points by mass lower than the final amount of addedchlorine. As used herein, the term “chlorine consumption rate” refers tothe amount of chlorine consumed in 5 minutes per kilogram of the rawmaterial PVC.

When chlorination is performed using the above method, a CPVC havingless nonuniformity in the chlorinated state and having excellent thermalstability can be obtained.

In the above chlorination method, preferably, the chlorination isperformed while the suspension is stirred. The suspension is stirredpreferably under such conditions that the ratio of the vortex volume(unit: L) to the total mass (kg) of the raw material PVC and water(Vortex volume/Total mass of raw material PVC and water) is 0.009 to0.143 (L/kg).

When the ratio is 0.009 (L/kg) or higher, chlorine in the gas phase inthe reaction vessel can be sufficiently taken in the liquid phase. Whenthe ratio is 0.143 (L/kg) or lower, the chlorine taken in the liquidphase is less likely to be re-released into the gas phase, allowinguniform chlorination.

The vortex volume means the volume of a vortex formed at the liquid-gasinterface during stirring.

For example, the vortex volume can be calculated using thermal fluid andpowder analysis software “R-FLOW” (produced by R-flow Corporation Ltd.).

Specifically, the vortex volume can be calculated based on the distancebetween the center of the stirring blade and the interface between thegas phase and the liquid phase in stirring. Here, the stirring blade,which is the stirring power, produces pressure in the liquid and setsthe liquid phase at a positive pressure and the gas phase at a negativepressure. This makes it possible to determine the interface between thegas phase and the liquid phase as the border between the positivepressure and the negative pressure.

The stirring blade rotation rate in stirring is preferably 10 to 500rpm. The capacity of the reaction vessel is preferably 0.01 m³ to 100m³.

The height of the stirring blade is preferably adjusted such that theratio of the distance from the liquid surface to the stirring blade tothe height of the liquid surface (Distance from liquid surface tostirring blade/Height of liquid surface) in stirring is 0.05 to 0.70(m/m). The height of the liquid surface means the distance from thebottom of the reaction vessel to the raw material liquid surface whenthe raw material is fed into the reaction vessel. The distance from theliquid surface to the stirring blade means the distance from the liquidsurface to the uppermost portion of the stirring blade.

The ratio of the stirring blade diameter to the reaction vessel diameter(Stirring blade diameter/Reaction vessel diameter) is preferably 0.3(m/m) or higher and preferably 0.9 (m/m) or lower.

In the chlorination method, the concentration of the chlorine introducedinto the reaction vessel is preferably 95% or higher.

In the chlorination method, the concentration of the chlorine dioxide inthe reaction vessel is preferably 5,000 ppm or less, more preferably2,500 ppm or less relative to the mass of the chlorine introduced. Thelower limit of the concentration of the chlorine dioxide is not limited,but is preferably 0.1 ppm or more, more preferably 1 ppm or more.

In the chlorination method, stabilized chlorine dioxide may be added asan additive, or a chlorine gas containing chlorine dioxide may be used.

A molded article can be produced by molding a resin composition formolding containing the chlorinated polyvinyl chloride resin of thepresent invention.

The present invention also encompasses a resin composition for moldingcontaining the chlorinated polyvinyl chloride resin of the presentinvention.

The lower limit of the amount of the chlorinated polyvinyl chlorideresin of the present invention in the resin composition for molding ofthe present invention is preferably 65% by mass, more preferably 70% bymass and the upper limit thereof is preferably 96% by mass, morepreferably 93% by mass.

The resin composition for molding of the present invention mayoptionally contain additives such as stabilizers, lubricants, processingaids, impact modifiers, heat resistance improvers, antioxidants,ultraviolet absorbents, light stabilizers, fillers, thermoplasticelastomers, and pigments.

Examples of the stabilizers include, but are not limited to, thermalstabilizers and thermal stabilization aids. Examples of the thermalstabilizers include, but are not limited to, organotin stabilizers, leadstabilizers, calcium-zinc stabilizers, barium-zinc stabilizers, andbarium-cadmium stabilizers.

Examples of the organotin stabilizers include dibutyl tin mercapto,dioctyl tin mercapto, dimethyl tin mercapto, dibutyl tin mercapto,dibutyl tin maleate, dibutyl tin maleate polymers, dioctyl tin maleate,dioctyl tin maleate polymers, dibutyl tin laurate, and dibutyl tinlaurate polymers.

Examples of the lead stabilizers include lead stearate, dibasic leadphosphite, and tribasic lead sulfate. These may be used singly or incombination of two or more thereof.

Examples of the thermal stabilization aids include, but are not limitedto, epoxidized soybean oil, phosphate, polyol, hydrotalcite, andzeolite. These may be used singly or in combination of two or morethereof.

Examples of the lubricants include internal lubricants and externallubricants.

The internal lubricants are used to reduce the fluid viscosity of themolten resin in molding to prevent the generation of frictional heat.Examples of the internal lubricants include, but are not limited to,butyl stearate, lauryl alcohol, stearyl alcohol, epoxidized soybean oil,glycerol monostearate, stearic acid, and bisamide. These may be usedsingly or in combinations of two or more.

The external lubricants are used to improve the slip effect betweenmetal surfaces and the molten resin in molding. Examples of the externallubricants include, but are not limited to, paraffin wax, polyolefinwaxes, ester waxes, and montanic acid wax. These may be used singly orin combinations of two or more.

Examples of the processing aids include, but are not limited to, acrylicprocessing aids such as alkyl acrylate-alkyl methacrylate copolymershaving a mass average molecular weight of 100,000 to 2,000,000. Examplesof the acrylic processing aids include, but are not limited to, n-butylacrylate-methyl methacrylate copolymers and 2-ethylhexyl acrylate-methylmethacrylate-butyl methacrylate copolymers. These may be used singly orin combination of two or more thereof.

Examples of the impact modifiers include, but are not limited to, methylmethacrylate-butadiene-styrene copolymers (MBS), chlorinatedpolyethylene, and acrylic rubber.

Examples of the heat resistance improvers include, but are not limitedto, α-methylstyrene resins and N-phenylmaleimide resins.

Examples of the antioxidants include, but are not limited to, phenolicantioxidants.

Examples of the light stabilizers include, but are not limited to,hindered amine light stabilizers.

Examples of the ultraviolet absorbents include, but are not limited to,salicylate ultraviolet absorbents, benzophenone ultraviolet absorbents,benzotriazole ultraviolet absorbents, and cyanoacrylate ultravioletabsorbents.

Examples of the fillers include, but are not limited to, calciumcarbonate and talc.

Examples of the pigments include, but are not limited to, organicpigments such as azo pigments, phthalocyanine pigments, threne pigments,and dye lake pigments; and inorganic pigments such as oxide pigments,molybdenum chromate pigments, sulfide/selenide pigments, andferrocyanide pigments.

Further, a molded article molded from the resin composition for moldingof the present invention is provided. The present invention alsoencompasses such a molded article.

The molding method may be any conventionally known molding method, forexample, extrusion molding or injection molding.

The molded article of the present invention has excellent thermalstability and good appearance, and is resistant to contamination due tofungi or the like because water droplets are less likely to remainthereon when water flows therethrough. The molded article of the presentinvention can therefore be suitably used in applications such asbuilding components, plumbing materials and equipment, and housingmaterials.

In the molded article of the present invention, the lower limit of thedeveloped interfacial area ratio (Sdr) is preferably 0.0001 and theupper limit thereof is preferably 0.003. This allows the molded articleto have a uniform surface.

The Sdr can be measured using a 3D measurement system (produced byKeyence Corporation, VR-3100), for example.

Advantageous Effects of Invention

The present invention can provide a chlorinated polyvinyl chloride resinthat enables excellent continuous productivity in molding and thatenables a molded article to have both processability andunevenness-preventing properties.

DESCRIPTION OF EMBODIMENTS

The present invention is hereinafter described in more detail withreference to examples; however, the present invention should not belimited to these examples.

EXAMPLE 1

A glass-lined reaction vessel having an inner capacity of 300 L wascharged with 130 kg of ion-exchanged water, 50 kg of a polyvinylchloride having an average degree of polymerization of 1,000, andstabilized chlorine dioxide. They were stirred to disperse the polyvinylchloride in water to prepare an aqueous suspension, and then the insideof the reaction vessel was heated to raise the temperature of theaqueous suspension to 100° C. The stabilized chlorine oxide was added insuch a proportion that the amount of chlorine dioxide was 200 ppmrelative to the mass of the chlorine introduced in chlorination.Subsequently, the inside of the reaction vessel was depressurized toremove oxygen (oxygen content 100 ppm). Thereafter, while stirring wasperformed with a stirring blade such that the vortex formed at theliquid-gas interface by stirring had a vortex volume of 7.5 L, chlorinewas introduced at a partial pressure of chlorine of 0.40 MPa, therebystarting thermal chlorination. At this time, the height of the stirringblade was adjusted such that the ratio of the distance from liquidsurface to the stirring blade to the height of the liquid surface(Distance from liquid surface to stirring blade/Height of liquidsurface) was 0.374 (m/m). The ratio of the stirring blade diameter tothe reaction vessel diameter (Stirring blade diameter/Reaction vesseldiameter) was 0.54 (m/m).

Then, the chlorination temperature was kept at 100° C. and the partialpressure of chlorine was kept at 0.40 MPa. After the amount of addedchlorine reached 4.2% by mass, addition of a 200 ppm hydrogen peroxidesolution was started at 15 ppm/Hr in terms of hydrogen peroxide relativeto the polyvinyl chloride, and the average chlorine consumption rate wasadjusted to 0.01 kg/PVC-kg·5 min. Thereafter, when the amount of addedchlorine reached 10.4% by mass, the supply of hydrogen peroxide solutionand chlorine gas was terminated, whereby chlorination was terminated.

Subsequently, unreacted chlorine was removed by nitrogen gas aeration,and the obtained chlorinated polyvinyl chloride resin slurry wasneutralized with sodium hydroxide, washed with water, dehydrated, andthen dried. Thus, a powdery, thermally chlorinated polyvinyl chlorideresin (amount of added chlorine: 10.4% by mass) was obtained.

EXAMPLES 2 to 13 AND COMPARATIVE EXAMPLES 1 to 11

Chlorinated polyvinyl chloride resins were obtained as in Example 1except that the average degree of polymerization of the polyvinylchloride, the ClO₂/Cl₂ concentration, the vortex volume in stirring, thedistance from the liquid surface to the stirring blade/the height of theliquid surface, the average chlorine consumption rate, and the amount of200 ppm hydrogen peroxide added were changed as shown in Tables 1 and 2.

(Evaluation)

The chlorinated polyvinyl chloride resins obtained in the examples andthe comparative examples were evaluated as follows. Table 1 shows theresults.

(1) Measurement of the Amount of Added Chlorine

The amount of added chlorine was measured for each of the obtainedchlorinated polyvinyl chloride resins in conformity with JIS K 7229.

(2) Molecular Structure Analysis

The molecular structure of each of the obtained chlorinated polyvinylchloride resins was analyzed in conformity with the NMR measurementmethod described in R. A. Komoroski, R. G. Parker, J. P. Shocker,Macromolecules, 1985, 18, 1257-1265 so as to determine the amount of thestructural units (a), (b), and (c).

The NMR measurement conditions were as follows.

-   -   Apparatus: FT-NMRJEOLJNM-AL-300    -   Measured nuclei: 13C (proton complete decoupling)    -   Pulse width: 90°    -   PD: 2.4 sec    -   Solvent: o-dichlorobenzene:deuterated benzene (C5D5)=3:1    -   Sample concentration: about 20%    -   Temperature: 110° C.    -   Reference material: central signal for benzene set to 128 ppm    -   Number of scans: 20,000

(3) Particle Raman Spectroscopy

Raman spectra of the obtained chlorinated polyvinyl chloride resins weremeasured using a micro-Raman spectrometer (produced by Thermo FisherScientific K.K., Almega XR). Here, the Raman spectra were measured forrandomly collected 50 particles of each of the obtained powderychlorinated polyvinyl chloride resin using a laser with a wavelength of532 nm at an exposure time of 1 second and a scan number of 32. Ramanspectroscopic analysis of particles themselves allows for obtaining thepeak intensities of the particle surfaces. The wavenumbers of the Ramanshifts were calibrated with the metal silicon peak at 520.5 cm ⁻¹.

The obtained Raman spectra were baseline-corrected by linearapproximation using a baseline from 515 cm⁻¹ to a local minimum observedat 750 to 950 cm⁻¹. Furthermore, the peak intensity B observed in therange of 600 to 650 cm⁻¹ (mainly 641 cm⁻¹) and the peak intensity Aobserved in the range of 660 to 700 cm⁻¹ (mainly 697 cm⁻¹) weremeasured, and the ratio (A/B) of the peak intensity A to the peakintensity B was calculated. The average of the A/B of the 50 particlesand the standard deviation of the A/B were calculated.

(4) Developed Interfacial Area Ratio (Sdr) (Production of ChlorinatedPolyvinyl Chloride Resin Composition)

An amount of 5.5 parts by mass of an impact resistance modifier wasadded to 100 parts by mass of each of the obtained chlorinated polyvinylchloride resins. Then, 1.5 parts by mass of a thermal stabilizer wasadded and mixed. The impact resistance modifier used was Kane Ace B-564(produced by Kaneka Corporation, methyl methacrylate-butadiene-styrenecopolymer). The thermal stabilizer used was TVS#1380 (produced by NittoKasei Co., Ltd., organotin stabilizer).

Further, 2.0 parts by mass of a polyethylene lubricant (produced byMitsui Chemicals, Inc., Hiwax 220MP) and 0.3 parts by mass of a fattyacid ester lubricant (produced by Emery Oleochemicals Japan Ltd., LOXIOLG-32) were added. They were uniformly mixed in a super mixer, whereby achlorinated polyvinyl chloride resin composition was obtained.

(Production of Extrusion-Molded Article)

The obtained chlorinated polyvinyl chloride resin composition was fedinto a twin-screw counter-rotating conical extruder with a diameter of50 mm (produced by Osada Seisakusho, SLM-50) to prepare a sheet-shapedmolded article with a thickness of 2 mm and a width of 80 mm at a resintemperature of 205° C., a back pressure of 130 kg/cm², and an extrusionamount of 40 kg/hr.

(Sdr Measurement)

The Sdr value of a surface of the obtained molded article was measuredusing a 3D measurement system (produced by Keyence Corporation,VR-3100). Each Sdr value shown in Table 1 is the average of fivemeasurement regions.

Sdr is a ratio representing the degree of increase in the surface areaof the measured region compared to the area of the measured region. Acompletely level surface has an Sdr of 0. A molded article having a lowSdr has excellent smoothness. Using such a molded article as, forexample, a pipe-shaped molded article for plumbing or the like canreduce noise when water is running.

(5) Residual Water Droplet

The obtained molded article (thickness 2 mm, width 80 mm, and length 150mm) was immersed in water for 10 seconds, taken out of the waterperpendicularly to the longitudinal direction at a speed of 150 mm/secusing tweezers, and held for 10 seconds. The surface of the moldedarticle was then observed to visually determine the presence or absenceof a water droplet having a diameter of 0.5 mm or more. The evaluationwas performed in accordance with the following criteria.

-   -   ○ (Good): No water droplet having a diameter of 0.5 mm or more        was observed.    -   × (Poor): Water droplet(s) having a diameter of 0.5 mm or more        was/were observed.

The absence of a water droplet on the surface of the molded articleindicates that the obtained molded article, for example a pipe-shapedmolded article, has few water droplets remaining thereon when waterflows therethrough, and thus has excellent antifungal properties.

(6) Scorch Marks (Discoloration) of Molded Article

The surface state of the obtained molded article was visually examinedand evaluated in accordance with the following criteria.

-   -   ○ (Good): No scorch mark (discoloration) was observed.    -   × (Poor): Scorch mark(s) (discoloration) was/were observed.

(7) Surface Shape (Unevenness)

The surface shape of the molded article was examined visually and bytouch, and evaluated in accordance with the following criteria.

-   -   ○ (Good): Neither the visual examination nor the touch        examination found surface irregularities.    -   Δ (Fair): The visual examination found no surface irregularities        but the touch examination found surface irregularities.    -   × (Poor) The visual examination found surface irregularities.

(8) Continuous Productivity

The obtained chlorinated polyvinyl chloride resin composition was fedinto a twin-screw counter-rotating conical extruder with a diameter of50 mm (produced by Osada Seisakusho, “SLM-50”) to prepare sheet-shapedmolded articles with a thickness of 2 mm and a width of 80 mm at a resintemperature of 205° C., a back pressure of 130 kg/cm², and an extrusionamount of 40 kg/hr. The time from the start of the molding to theoccurrence of a scorch mark (discoloration) in the obtained moldedarticle was measured, and the continuous productivity was evaluated.

A longer time before the occurrence of a scorch mark (discoloration) inthe molded article indicates that the chlorinated polyvinyl chlorideresin is less likely to contaminate the die surface and enablesexcellent continuous productivity when products are continuouslyproduced by repeating similar operations for a long time.

TABLE 1 Examples 1 2 3 4 5 Production Raw material Average degree ofpolymerization 1000 1000 1000 1000 1000 method PVC Charge amount kg 5050 50 50 50 Water Ion-exchanged water kg 130 130 130 130 130 AdditiveClO₂/Cl₂ ppm 200 4,900 200 200 200 concentration Chlorination Reactiontemperature ° C. 100 100 100 100 100 conditions Reaction pressure Mpa0.40 0.40 0.40 0.40 0.40 PVC + water kg 180 180 180 180 180 Vortexvolume in L 7.5 20.5 7.6 7.5 7.5 stirring Vortex volume/ L/kg 0.0420.114 0.042 0.042 0.042 (PVC + water) (Distance from m/m 0.374 0.4960.374 0.374 0.374 liquid surface to stirring blade)/ Height of liquidsurface Average chlorine kg/pvc-kg · 0.01 0.005 0.01 0.011 0.012consumption rate 5 min 200 ppm hydrogen ppm/hr 15 15 15 15 15 peroxideChlorinated Amount of added chlorine mass % 10.4 10.5 3.3 0.2 3.3polyvinyl Structure Structural unit (a) mol % 36.5 36.1 80.2 98.8 80.6chloride —CH₂—CHCl— resin Structural unit (b) mol % 24 24.2 7.1 0.1 6—CH₂—CCl₂— Structural unit (c) mol % 39.5 39.7 12.7 1.1 13.4 —CHCl—CHCl—Raman Peak intensity Average 1.249 1.260 0.550 0.731 0.796 spectroscopicA/B Standard 0.038 0.076 0.008 0.011 0.013 analysis deviation (Peakaverage of A/B) + 1.445 1.536 0.639 0.836 0.910 (Standarddeviation)^(1/2) Molded Sdr 0.0010 0.0028 0.0015 0.0005 0.0012 articleResidual water droplet ∘ ∘ ∘ ∘ ∘ Scorch mark (discoloration) ∘ ∘ ∘ ∘ ∘Surface shape (unevenness) ∘ ∘ ∘ ∘ ∘ Continuous productivity (hr) 8.27.5 4.8 6 7 Examples 6 7 8 9 10 Production Raw material Average degreeof polymerization 1000 1000 350 450 1900 method PVC Charge amount kg 5050 50 50 50 Water Ion-exchanged water kg 130 130 130 130 130 AdditiveClO₂/Cl₂ ppm 200 200 200 200 200 concentration Chlorination Reactiontemperature ° C. 100 100 100 100 100 conditions Reaction pressure Mpa0.40 0.40 0.40 0.40 0.40 PVC + water kg 180 180 180 180 180 Vortexvolume in L 7.6 7.5 7.4 7.5 7.5 stirring Vortex volume/ L/kg 0.042 0.0420.041 0.042 0.042 (PVC + water) (Distance from m/m 0.374 0.374 0.3740.374 0.374 liquid surface to stirring blade)/ Height of liquid surfaceAverage chlorine kg/pvc-kg · 0.007 0.006 0.008 0.009 0.008 consumptionrate 5 min 200 ppm hydrogen ppm/hr 15 15 15 15 15 peroxide ChlorinatedAmount of added chlorine mass % 13.3 15 10.3 10.5 12 polyvinyl StructureStructural unit (a) mol % 19.3 5.2 36.9 35.8 27.0 chloride —CH₂—CHCl—resin Structural unit (b) mol % 29.1 39.9 33 24 24.2 —CH₂—CCl₂—Structural unit (c) mol % 51.6 54.9 30.1 40.2 48.8 —CHCl—CHCl— RamanPeak intensity Average 1.461 1.860 1.193 1.203 1.348 spectroscopic A/BStandard 0.052 0.078 0.023 0.028 0.068 analysis deviation (Peak averageof A/B) + 1.689 2.139 1.345 1.370 1.609 (Standard deviation)^(1/2)Molded Sdr 0.0025 0.0028 0.0019 0.0020 0.0029 article Residual waterdroplet ∘ ∘ ∘ ∘ ∘ Scorch mark (discoloration) ∘ ∘ ∘ ∘ ∘ Surface shape(unevenness) ∘ ∘ ∘ ∘ ∘ Continuous productivity (hr) 6.6 5.1 4 4.4 4.5Examples 11 12 13 Production Raw material Average degree ofpolymerization 1000 1000 1000 method PVC Charge amount kg 50 50 50 WaterIon-exchanged water kg 130 130 130 Additive ClO₂/Cl₂ ppm 2,450 200 200concentration Chlorination Reaction temperature ° C. 100 100 100conditions Reaction pressure Mpa 0.40 0.40 0.40 PVC + water kg 180 180180 Vortex volume in L 7.5 2 25.2 stirring Vortex volume/ L/kg 0.0420.011 0.140 (PVC + water) (Distance from m/m 0.374 0.118 0.684 liquidsurface to stirring blade)/ Height of liquid surface Average chlorinekg/pvc-kg · 0.006 0.005 0.014 consumption rate 5 min 200 ppm hydrogenppm/hr 15 15 15 peroxide Chlorinated Amount of added chlorine mass %10.4 10.5 10.6 polyvinyl Structure Structural unit (a) mol % 35.0 35.835.3 chloride —CH₂—CHCl— resin Structural unit (b) mol % 38.8 23.2 24—CH₂—CCl₂— Structural unit (c) mol % 26.2 41 40.7 —CHCl—CHCl— Raman Peakintensity Average 1.250 1.268 1.260 spectroscopic A/B Standard 0.0850.078 0.076 analysis deviation (Peak average of A/B) + 1.542 1.547 1.536(Standard deviation)^(1/2) Molded Sdr 0.0029 0.0025 0.0026 articleResidual water droplet ∘ ∘ ∘ Scorch mark (discoloration) ∘ ∘ ∘ Surfaceshape (unevenness) ∘ ∘ ∘ Continuous productivity (hr) 5.6 5.1 7.6

TABLE 2 Comparative Examples 1 2 3 4 5 6 Production Raw material Averagedegree of polymerization 1000 1000 1000 2100 1000 1000 method PVC Chargeamount kg 50 50 50 50 50 50 Water Ion-exchanged water kg 130 130 130 130130 130 Additive ClO₂/Cl₂ ppm 7,350 200 200 200 5,100 200 concentrationChlorination Reaction temperature ° C. 100 100 100 100 100 100conditions Reaction pressure Mpa 0.40 0.40 0.40 0.40 0.40 0.40 PVC +water kg 180 180 180 180 180 180 Vortex volume in L 27.2 30.6 0.9 28.81.1 1.5 stirring Vortex volume/ L/kg 0.151 0.170 0.005 0.160 0.006 0.008(PVC + water) (Distance from m/m 0.809 0.970 0.032 0.905 0.040 0.040liquid surface to stirring blade)/ Height of liquid surface Averagechlorine kg/pvc-kg · 0.003 0.025 0.005 0.020 0.005 0.004 consumptionrate 5 min 200 ppm hydrogen ppm/hr 15 15 15 15 15 15 peroxideChlorinated Amount of added chlorine mass % 10.6 3.3 17.2 12.2 10.5 10.6polyvinyl Structure Structural unit (a) mol % 35.6 80.5 1.0 25.4 35.235.4 chloride —CH₂—CHCl— resin Structural unit (b) mol % 40.3 8 41.2 3539 44 —CH₂—CCl₂— Structural unit (c) mol % 24.1 11.5 57.8 39.6 25.8 20.6—CHCl—CHCl— Raman Peak intensity Average 1.254 0.484 2.012 1.368 1.2541.251 spectroscopic A/B Standard 0.091 0.005 0.079 0.093 0.091 0.092analysis deviation (Peak average of A/B) + 1.556 0.555 2.293 1.673 1.5561.554 (Standard deviation)^(1/2) Molded Sdr 0.0135 0.0035 0.0071 0.00510.0108 0.0029 article Residual water droplet x ∘ x x x ∘ Scorch mark(discoloration) x x x x x x Surface shape (unevenness) x ∘ x x x ∘Continuous productivity (hr) 1.5 2.1 1.9 2 2.3 2 Comparative Examples 78 9 10 11 Production Raw material Average degree of polymerization 10001000 1000 1000 1000 method PVC Charge amount kg 50 50 50 50 50 WaterIon-exchanged water kg 130 130 130 130 130 Additive ClO₂/Cl₂ ppm 200 200200 200 200 concentration Chlorination Reaction temperature ° C. 100 100100 100 100 conditions Reaction pressure Mpa 0.40 0.40 0.40 0.40 0.40PVC + water kg 180 180 180 180 180 Vortex volume in L 27.2 1.8 1.4 2526.2 stirring Vortex volume/ L/kg 0.151 0.010 0.008 0.139 0.146 (PVC +water) (Distance from m/m 0.809 0.040 0.052 0.809 0.684 liquid surfaceto stirring blade)/ Height of liquid surface Average chlorine kg/pvc-kg· 0.016 0.004 0.004 0.016 0.016 consumption rate 5 min 200 ppm hydrogenppm/hr 15 15 15 15 15 peroxide Chlorinated Amount of added chlorine mass% 10.5 10.6 10.5 10.5 10.3 polyvinyl Structure Structural unit (a) mol %35.0 35.3 35.2 35.1 35.3 chloride —CH₂—CHCl— resin Structural unit (b)mol % 28 40.5 41 28.5 27 —CH₂—CCl₂— Structural unit (c) mol % 37 24.223.8 36.4 37.7 —CHCl—CHCl— Raman Peak intensity Average 1.255 1.2561.257 1.255 1.254 spectroscopic A/B Standard 0.092 0.095 0.096 0.0950.097 analysis deviation (Peak average of A/B) + 1.558 1.564 1.567 1.5631.565 (Standard deviation)^(1/2) Molded Sdr 0.0033 0.0025 0.0028 0.00350.0033 article Residual water droplet ∘ ∘ ∘ ∘ ∘ Scorch mark(discoloration) x x x x x Surface shape (unevenness) Δ ∘ ∘ Δ ΔContinuous productivity (hr) 2.5 3.8 3.5 3.5 3.5

INDUSTRIAL APPLICABILITY

The present invention can provide a chlorinated polyvinyl chloride resinthat enables excellent continuous productivity in molding and thatenables a molded article to have both processability andunevenness-preventing properties.

1. A chlorinated polyvinyl chloride resin having, in Raman measurementby Raman spectroscopy, an average of a ratio (A/B) of a peak intensity Aobserved in a range of 660 to 700 cm⁻¹ to a peak intensity B observed ina range of 600 to 650 cm ¹ of 0.50 to 2.00, and a standard deviation ofthe A/B of 0.090 or less.
 2. A resin composition for molding comprisingthe chlorinated polyvinyl chloride resin according to claim
 1. 3. Amolded article molded from the resin composition for molding accordingto claim 2.